TWI531153B - Audio amplifier apparatus - Google Patents

Audio amplifier apparatus Download PDF

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Publication number
TWI531153B
TWI531153B TW101111119A TW101111119A TWI531153B TW I531153 B TWI531153 B TW I531153B TW 101111119 A TW101111119 A TW 101111119A TW 101111119 A TW101111119 A TW 101111119A TW I531153 B TWI531153 B TW I531153B
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Taiwan
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coupled
switch
output
voltage value
audio
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TW101111119A
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Chinese (zh)
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TW201340590A (en
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陳宜隆
黃信傑
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微晶片科技公司
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Priority to TW101111119A priority Critical patent/TWI531153B/en
Priority to CN201210142044.9A priority patent/CN103369427B/en
Priority to US13/469,085 priority patent/US9257942B2/en
Publication of TW201340590A publication Critical patent/TW201340590A/en
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Publication of TWI531153B publication Critical patent/TWI531153B/en

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
    • H03F1/305—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in case of switching on or off of a power supply
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
    • H03F3/183—Low-frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only
    • H03F3/187—Low-frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only in integrated circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F3/211—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/20—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F2203/21—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F2203/211—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers
    • H03F2203/21109—An input signal being distributed by switching to a plurality of paralleled power amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/20—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F2203/21—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F2203/211—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers
    • H03F2203/21175—An output signal of a power amplifier being on/off switched
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/20—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F2203/21—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F2203/211—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers
    • H03F2203/21196—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers the supply voltage of a power amplifier being switchable controlled

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Multimedia (AREA)
  • Amplifiers (AREA)

Description

音訊放大裝置Audio amplification device

本發明是有關於一種放大裝置，且特別是有關於一種可抑制爆音雜訊(pop noise)的音訊放大裝置。The present invention relates to an amplifying device, and more particularly to an audio amplifying device capable of suppressing pop noise.

一般電子產品在開關機過程中，其揚聲器常常會發出爆音雜訊而讓使用者聽起來很不舒服。究其原因，一般是因為用以驅動揚聲器的音頻放大裝置的輸出端電壓突然激烈變化，進而產生突波電流(spike current)而使得揚聲器產生了尖銳刺耳的噪音。除了造成使用者在使用上的不舒適外，有時過大的突波電流更會破壞揚聲器中高敏感度的元件，所以很多音頻放大裝置都將如何消除爆音雜訊作為主要的設計目標。In general electronic products, during the process of switching on and off, the speakers often emit pop noise and make the user feel uncomfortable. The reason is generally because the voltage at the output of the audio amplifying device for driving the speaker suddenly changes drastically, thereby generating a spike current, which causes the speaker to produce sharp and harsh noise. In addition to causing user discomfort in use, sometimes excessive surge currents can damage high-sensitivity components in the speaker, so many audio amplifiers will eliminate pop noise as the main design goal.

在現有的作法中，一般係以額外的預充電電路來對音頻放大裝置的輸出端進行預充電，使音頻放大裝置的輸出端上之電壓值緩慢的提升以降低開關機時的爆音雜訊。然而，揚聲器在預充電結束到切換至正常操作狀態時，音頻放大裝置的突然導通亦會造成一定程度的爆音雜訊。此外，進行預充電的動作亦會使得音頻放大裝置的開機速度受到影響，而無法有效地提升音頻放大裝置的品質。In the existing method, the output terminal of the audio amplifying device is generally pre-charged with an additional pre-charging circuit, so that the voltage value at the output end of the audio amplifying device is slowly increased to reduce the popping noise when the machine is turned on and off. However, when the speaker is switched to the normal operating state at the end of the pre-charging, the sudden turn-on of the audio amplifying device also causes a certain degree of popping noise. In addition, the pre-charging operation also affects the booting speed of the audio amplifying device, and cannot effectively improve the quality of the audio amplifying device.

本發明提供一種音訊放大裝置，其可利用預充電單元逐漸地對輸出端進行充電，並且依據輸出端的充電狀態切換利用具有不同驅動能力的放大模組來驅動揚聲器。The invention provides an audio amplifying device which can gradually charge an output terminal by using a pre-charging unit, and switch the driving module by using an amplifying module having different driving capabilities according to the charging state of the output end.

本發明提出一種音訊放大裝置，適於驅動揚聲器，包括預充電單元、第一放大模組以及第二放大模組。預充電單元透過輸出端耦接揚聲器，且預充電單元依據第一控制信號提供驅動電流對揚聲器進行預充電，以逐漸地增加輸出端上的電壓值。第一放大模組耦接至輸出端，且第一放大模組用以依據第一控制信號來接收音訊信號，並放大音訊信號以輸出第一放大信號來驅動揚聲器。第二放大模組耦接至輸出端，且第二放大模組用以依據第二控制信號來接收音訊信號，並放大音訊信號以輸出第二放大信號來驅動揚聲器。其中，預充電單元依據比對輸出端上的電壓值以及預設電壓值來產生第二控制信號。The invention provides an audio amplifying device suitable for driving a speaker, comprising a pre-charging unit, a first amplifying module and a second amplifying module. The pre-charging unit is coupled to the speaker through the output end, and the pre-charging unit provides a driving current according to the first control signal to pre-charge the speaker to gradually increase the voltage value at the output end. The first amplification module is coupled to the output end, and the first amplification module is configured to receive the audio signal according to the first control signal, and amplify the audio signal to output the first amplified signal to drive the speaker. The second amplification module is coupled to the output end, and the second amplification module is configured to receive the audio signal according to the second control signal, and amplify the audio signal to output the second amplified signal to drive the speaker. The pre-charging unit generates the second control signal according to the voltage value on the comparison output and the preset voltage value.

在本發明之一實施例中，第一放大模組的驅動能力低於第二放大模組的驅動能力。In an embodiment of the invention, the driving capability of the first amplifying module is lower than the driving capability of the second amplifying module.

在本發明之一實施例中，預設電壓值等於音訊放大裝置所接收的電源電壓的電壓值的N分之一，N為正整數。In an embodiment of the invention, the preset voltage value is equal to one-Nth of a voltage value of the power supply voltage received by the audio amplifying device, and N is a positive integer.

在本發明之一實施例中，當預充電單元判斷輸出端上的電壓值等於預設電壓值時，預充電單元使第二控制信號致能，並藉以使第二放大模組接收音訊信號，以產生第二放大信號。In an embodiment of the present invention, when the pre-charging unit determines that the voltage value on the output end is equal to the preset voltage value, the pre-charging unit enables the second control signal, and thereby causes the second amplifying module to receive the audio signal. To generate a second amplified signal.

在本發明之一實施例中，當第二控制信號被致能時，第一控制信號對應被禁能，使預充電單元停止對揚聲器所進行的預充電動作，並使第一放大模組停止接收音訊信號。In an embodiment of the present invention, when the second control signal is enabled, the first control signal is disabled, the pre-charging unit stops the pre-charging action performed on the speaker, and the first amplifying module is stopped. Receive audio signals.

在本發明之一實施例中，其中第一放大模組包括第一放大器以及第一電容。第一放大器具有輸入端與輸出端，其輸入端接收音訊信號，且其輸出端輸出第一放大信號。第一電容具有第一端與第二端，其第一端耦接第一放大器的輸入端，且其第二端耦接第一放大器的輸出端。In an embodiment of the invention, the first amplification module includes a first amplifier and a first capacitor. The first amplifier has an input end and an output end, the input end of which receives the audio signal, and the output end of which outputs the first amplified signal. The first capacitor has a first end and a second end, the first end of which is coupled to the input end of the first amplifier, and the second end of the first capacitor is coupled to the output end of the first amplifier.

在本發明之一實施例中，其中第一放大模組更包括第一電阻、第一開關以及第二開關。第一電阻具有第一端與第二端，其第一端耦接第一放大器的輸出端。第一開關具有第一端與第二端，且第一開關依據第一控制信號決定是否導通。第一開關的第一端接收音訊信號，且其第二端耦接第一放大器的輸入端與第一電容的第一端。第二開關具有第一端與第二端，且第二開關依據第一控制信號決定是否導通。第二開關的第一端耦接第一電阻的第二端，且其第二端耦接第一放大器的輸出端。其中，當輸出端上的電壓值不等於預設電壓值時，第一開關與第二開關依據第一控制信號而導通，以及當輸出端上的電壓值等於預設電壓值時，第一開關與第二開關依據第一控制信號而截止。In an embodiment of the invention, the first amplification module further includes a first resistor, a first switch, and a second switch. The first resistor has a first end and a second end, the first end of which is coupled to the output end of the first amplifier. The first switch has a first end and a second end, and the first switch determines whether to conduct according to the first control signal. The first end of the first switch receives the audio signal, and the second end of the first switch is coupled to the input end of the first amplifier and the first end of the first capacitor. The second switch has a first end and a second end, and the second switch determines whether to conduct according to the first control signal. The first end of the second switch is coupled to the second end of the first resistor, and the second end of the second switch is coupled to the output end of the first amplifier. Wherein, when the voltage value on the output end is not equal to the preset voltage value, the first switch and the second switch are turned on according to the first control signal, and when the voltage value on the output end is equal to the preset voltage value, the first switch And the second switch is turned off according to the first control signal.

在本發明之一實施例中，第二放大模組包括第二放大器以及二電容。第二放大器具有輸入端與輸出端，其輸入端接收音訊信號，且其輸出端輸出第二放大信號。第二電容具有第一端與第二端，其第一端耦接第二放大器的輸入端，且其第二端耦接第二放大器的輸出端。In an embodiment of the invention, the second amplification module includes a second amplifier and two capacitors. The second amplifier has an input end and an output end, the input end of which receives the audio signal, and the output end of which outputs the second amplified signal. The second capacitor has a first end and a second end, the first end of which is coupled to the input end of the second amplifier, and the second end of the second capacitor is coupled to the output end of the second amplifier.

在本發明之一實施例中，第二放大模組更包括第三開關。第三開關具有第一端與第二端，且第三開關依據第二控制信號決定是否導通。第三開關的第一端接收音訊信號，且其第二端耦接第二放大器的輸入端與第二電容的第一端。其中，當輸出端上的電壓值不等於預設電壓值時，第三開關依據第二控制信號而截止，以及當輸出端上的電壓值等於預設電壓值時，第三開關依據第二控制信號而導通。In an embodiment of the invention, the second amplification module further includes a third switch. The third switch has a first end and a second end, and the third switch determines whether to conduct according to the second control signal. The first end of the third switch receives the audio signal, and the second end of the third switch is coupled to the input end of the second amplifier and the first end of the second capacitor. Wherein, when the voltage value on the output terminal is not equal to the preset voltage value, the third switch is turned off according to the second control signal, and when the voltage value on the output terminal is equal to the preset voltage value, the third switch is according to the second control The signal is turned on.

在本發明之一實施例中，音訊放大裝置更包括第一回授電阻以及第二回授電阻。第一回授電阻具有第一端與第二端，其第一端接收音訊信號，且其第二端耦接第一放大器與第二放大器的輸入端。第二回授電阻具有第一端與第二端，其第一端耦接第二電阻的第二端以及第一放大器與第二放大器的輸入端，且其第二端耦接預充電單元以及第一放大器與第二放大器的輸出端。In an embodiment of the invention, the audio amplification device further includes a first feedback resistor and a second feedback resistor. The first feedback resistor has a first end and a second end, the first end of which receives the audio signal, and the second end of which is coupled to the input ends of the first amplifier and the second amplifier. The second feedback resistor has a first end and a second end, the first end of which is coupled to the second end of the second resistor and the input ends of the first amplifier and the second amplifier, and the second end of the second feedback is coupled to the pre-charging unit and The output of the first amplifier and the second amplifier.

在本發明之一實施例中，前置放大器具有第一輸入端、第二輸入端與輸出端，其第一輸入端耦接音訊放大裝置的輸出端，其第二輸入端耦接預設電壓，且其輸出端耦接第一放大模組與第二放大模組。In an embodiment of the present invention, the preamplifier has a first input end, a second input end, and an output end, the first input end of which is coupled to the output end of the audio amplifying device, and the second input end is coupled to the preset voltage. And the output end is coupled to the first amplifying module and the second amplifying module.

在本發明之一實施例中，預充電單元包括電流源、第一預充電開關、延遲電容以及延遲電阻。電流源依據電源電壓提供驅動電流。第一預充電開關具有第一端與第二端，且第一預充電開關依據第一控制信號決定是否導通，其中第一預充電開關的第一端耦接電流源。延遲電容具有第一端與第二端，其第一端耦接第一預充電開關的第二端，且其第二端耦接接地電壓。延遲電阻具有第一端與第二端，其第一端耦接第一預充電開關的第二端與延遲電容的第一端，且其第二端耦接第一放大模組與第二放大模組。其中，當第一預充電開關依據第一控制信號而導通時，驅動電流藉由延遲電容與延遲電阻逐漸增加輸出端上的電壓值。In an embodiment of the invention, the pre-charging unit includes a current source, a first pre-charge switch, a delay capacitor, and a delay resistor. The current source provides drive current based on the supply voltage. The first pre-charge switch has a first end and a second end, and the first pre-charge switch determines whether to conduct according to the first control signal, wherein the first end of the first pre-charge switch is coupled to the current source. The delay capacitor has a first end and a second end, the first end of which is coupled to the second end of the first pre-charge switch, and the second end of which is coupled to the ground voltage. The delay resistor has a first end and a second end, the first end of which is coupled to the second end of the first precharge switch and the first end of the delay capacitor, and the second end of the second preamplifier is coupled to the first amplifying module and the second end Module. Wherein, when the first pre-charge switch is turned on according to the first control signal, the driving current gradually increases the voltage value at the output end by the delay capacitor and the delay resistor.

在本發明之一實施例中，預充電單元更包括第二預充電開關。第二預充電開關具有第一端與第二端，且第二預充電開關依據第一控制信號決定是否導通，其中第二預充電開關的第一端耦接延遲電阻的第二端，且其第二端耦接音訊放大裝置的輸出端。In an embodiment of the invention, the pre-charging unit further includes a second pre-charging switch. The second pre-charge switch has a first end and a second end, and the second pre-charge switch determines whether to conduct according to the first control signal, wherein the first end of the second pre-charge switch is coupled to the second end of the delay resistor, and The second end is coupled to the output of the audio amplifying device.

在本發明之一實施例中，當預充電單元判斷輸出端上的電壓值不等於預設電壓值時，第一預充電開關與第二預充電開關依據第一控制信號而導通，以及當預充電單元判斷輸出端上的電壓值等於預設電壓值時，第一預充電開關與第二預充電開關依據第一控制信號而截止。In an embodiment of the present invention, when the pre-charging unit determines that the voltage value on the output end is not equal to the preset voltage value, the first pre-charge switch and the second pre-charge switch are turned on according to the first control signal, and when pre- When the charging unit determines that the voltage value on the output terminal is equal to the preset voltage value, the first pre-charge switch and the second pre-charge switch are turned off according to the first control signal.

在本發明之一實施例中，預充電單元更包括比較器以及閂鎖器。比較器具有第一輸入端、第二輸入端與輸出端，其第一輸入端耦接預設電壓，其第二輸入端耦接第二預充電開關的第二端以及音訊放大裝置的輸出端，且其輸出端輸出比較信號，其中比較器依據音訊放大裝置的輸出端上的電壓值以及預設電壓提供的預設電壓值的比對結果產生比較信號。閂鎖器耦接比較器的輸出端，且閂鎖器依據閂鎖比較信號來產生第二控制信號。In an embodiment of the invention, the pre-charging unit further includes a comparator and a latch. The comparator has a first input end, a second input end and an output end, the first input end is coupled to the preset voltage, and the second input end is coupled to the second end of the second pre-charge switch and the output end of the audio amplifying device And the output end outputs a comparison signal, wherein the comparator generates a comparison signal according to the comparison result of the voltage value on the output end of the audio amplifying device and the preset voltage value provided by the preset voltage. The latch is coupled to the output of the comparator, and the latch generates a second control signal based on the latch comparison signal.

在本發明之一實施例中，第一控制信號與第二控制信號互為反相。In an embodiment of the invention, the first control signal and the second control signal are mutually inverted.

在本發明之一實施例中，揚聲器為喇叭。In an embodiment of the invention, the speaker is a horn.

基於上述，本發明實施例之音訊放大裝置利用預充電單元對揚聲器進行預充電，以逐漸地提升音訊放大裝置的輸出端上的電壓值，並且依據預充電的狀態切換具有不同驅動能力的放大模組，使得揚聲器自預充電狀態切換至正常操作時所可能產生的突波電流得以被有效地消除。此外，由於在預充電期間音訊放大裝置已預先建立其放大模組內部的電壓準位，使得揚聲器的電源開啟後得以快速進入正常操作狀態。因此，本發明實施例有效地降低了揚聲器電源開啟時的爆音雜訊，同時亦縮短了揚聲器的開機速度，進而提升了使用者收聽的品質與舒適度。Based on the above, the audio amplifying device of the embodiment of the present invention precharges the speaker by using the pre-charging unit to gradually increase the voltage value at the output end of the audio amplifying device, and switches the amplification mode with different driving capabilities according to the state of pre-charging. The group, so that the surge current that may be generated when the speaker is switched from the pre-charge state to the normal operation can be effectively eliminated. In addition, since the audio amplifying device has previously established the voltage level inside the amplifying module during pre-charging, the power of the speaker is turned on and quickly enters the normal operating state. Therefore, the embodiment of the invention effectively reduces the popping noise when the speaker power is turned on, and also shortens the booting speed of the speaker, thereby improving the quality and comfort of the user.

為讓本發明之上述特徵和優點能更明顯易懂，下文特舉實施例，並配合所附圖式作詳細說明如下。The above described features and advantages of the present invention will be more apparent from the following description.

本發明實施例提出音訊放大裝置，其可在電源開啟時對揚聲器進行預充電的動作，並依據預充電的狀態而切換具有不同驅動能力的放大模組來放大音訊信號，使得揚聲器不會因為電源狀態切換時的突波電流而產生爆音雜訊。為了使本發明之內容更容易明瞭，以下特舉實施例作為本發明確實能夠據以實施的範例。另外，凡可能之處，在圖式及實施方式中使用相同標號的元件/構件/步驟代表相同或類似部分。The embodiment of the invention provides an audio amplifying device, which can pre-charge the speaker when the power is turned on, and switch the amplifying module with different driving capabilities according to the pre-charging state to amplify the audio signal, so that the speaker does not be powered The glitch current during state switching produces pop noise. In order to make the content of the present invention easier to understand, the following specific embodiments are illustrative of the embodiments of the present invention. In addition, wherever possible, the elements and/

圖1繪示本發明一實施例之音訊放大裝置100的示意圖。在本實施例中，音訊放大裝置100包括預充電單元110、第一放大模組120以及第二放大模組130。在本實施例中，所述之音訊放大裝置100適用於驅動揚聲器140，使揚聲器140得以將音訊信號s_a轉換為聲音輸出，其中揚聲器140例如為喇叭。FIG. 1 is a schematic diagram of an audio amplifying apparatus 100 according to an embodiment of the present invention. In the embodiment, the audio amplifying device 100 includes a pre-charging unit 110, a first amplifying module 120, and a second amplifying module 130. In the embodiment, the audio amplifying device 100 is adapted to drive the speaker 140, so that the speaker 140 can convert the audio signal s_a into a sound output, wherein the speaker 140 is, for example, a speaker.

請參照圖1，預充電單元110透過輸出端OT耦接揚聲器140，用以依據第一控制信號s_c1提供驅動電流I_d對揚聲器140進行預充電，以逐漸地增加輸出端OT上的電壓值。第一放大模組120耦接至輸出端OT，用以依據第一控制信號s_c1來接收音訊信號s_a，並放大音訊信號s_a以輸出第一放大信號s_amp1來驅動揚聲器140。相似地，第二放大模組130耦接至輸出端OT，用以依據第二控制信號s_c2來接收音訊信號s_a，並放大音訊信號s_a以輸出第二放大信號s_amp2來驅動揚聲器140。其中，第一放大模組120的驅動能力小於第二放大模組的驅動能力。Referring to FIG. 1 , the pre-charging unit 110 is coupled to the speaker 140 through the output terminal OT for pre-charging the speaker 140 according to the first control signal s_c1 to provide a driving current I_d to gradually increase the voltage value on the output terminal OT. The first amplifying module 120 is coupled to the output terminal OT for receiving the audio signal s_a according to the first control signal s_c1, and amplifying the audio signal s_a to output the first amplified signal s_amp1 to drive the speaker 140. Similarly, the second amplifying module 130 is coupled to the output terminal OT for receiving the audio signal s_a according to the second control signal s_c2, and amplifying the audio signal s_a to output the second amplified signal s_amp2 to drive the speaker 140. The driving capability of the first amplifying module 120 is smaller than the driving capability of the second amplifying module.

具體而言，圖2繪示依照圖1實施例之輸出端OT的暫態響應的示意圖，其中圖2之橫軸為輸出端OT的充電時間t，而其縱軸為輸出端OT的電壓值v_out。請同時參照圖1與圖2，當揚聲器140的電源被開啟時，第一控制信號s_c1將被致能，而使得預充電單元110依據致能的第一控制信號s_c1使電源電壓V_DD透過輸出端OT對揚聲器140進行偏壓，以提供驅動電流I_d，並使電壓值v_out在預充電期間t_soft(例如等於數毫秒)內逐漸地增加，直到電壓值v_out等於預設電壓值v_p時，揚聲器140進入正常操作的狀態。在此同時，預充電單元110停止對揚聲器140進行預充電。請注意，圖2的曲線斜率越小，在達到固定的預設電壓值v_p之情況下，代表電壓值v_out預充電期間t_soft越長，電壓增加的幅度越緩慢，因此得以防止電壓值v_out突然的改變而產生的爆音雜訊。Specifically, FIG. 2 is a schematic diagram showing the transient response of the output terminal OT according to the embodiment of FIG. 1. The horizontal axis of FIG. 2 is the charging time t of the output terminal OT, and the vertical axis thereof is the voltage value of the output terminal OT. V_out. Referring to FIG. 1 and FIG. 2 simultaneously, when the power of the speaker 140 is turned on, the first control signal s_c1 is enabled, so that the pre-charging unit 110 passes the power supply voltage V_DD through the output according to the enabled first control signal s_c1. The OT biases the speaker 140 to provide the drive current I_d and gradually increases the voltage value v_out during the pre-charge period t_soft (eg, equal to several milliseconds) until the voltage value v_out is equal to the preset voltage value v_p, the speaker 140 enters The state of normal operation. At the same time, the pre-charging unit 110 stops precharging the speaker 140. Please note that the smaller the slope of the curve of FIG. 2 is, the longer the pre-charge period t_soft is, the slower the voltage increase is, the longer the voltage value v_out is suddenly. The popping noise generated by the change.

詳細來說，當揚聲器140的電源被開啟時，第一放大模組120將同時依據致能的第一控制信號s_c1接收音訊信號s_a，並且在放大音訊信號s_a後，輸出第一放大信號s_amp1來驅動揚聲器140。此外，由於第二控制信號s_c2仍為禁能的狀態，因此第二放大模組130並未進行任何動作。In detail, when the power of the speaker 140 is turned on, the first amplifying module 120 simultaneously receives the audio signal s_a according to the enabled first control signal s_c1, and after amplifying the audio signal s_a, outputs the first amplified signal s_amp1. The speaker 140 is driven. In addition, since the second control signal s_c2 is still disabled, the second amplification module 130 does not perform any action.

隨著充電時間的增加，電壓值v_out亦將持續的增加，直到預充電單元110判斷輸出端OT上的電壓值v_out等於預設電壓值v_p時，預充電單元110致能第二控制信號s_c2，並且對應的禁能第一控制信號s_c1，使得預充電單元110停止對揚聲器140進行預充電動作，亦即第一控制信號s_c1與第二控制信號s_c2在本實施例中互為反相信號。因此，在預充電期間t_soft後，電壓值v_out將維持在預設電壓值v_p。As the charging time increases, the voltage value v_out will continue to increase until the pre-charging unit 110 determines that the voltage value v_out on the output terminal OT is equal to the preset voltage value v_p, the pre-charging unit 110 enables the second control signal s_c2, And the corresponding first control signal s_c1 is disabled, so that the pre-charging unit 110 stops pre-charging the speaker 140, that is, the first control signal s_c1 and the second control signal s_c2 are mutually inverted signals in this embodiment. Therefore, after the precharge period t_soft, the voltage value v_out will be maintained at the preset voltage value v_p.

值得注意的是，所述之預設電壓值v_p等於音訊放大裝置100所接收的電源電壓V_DD的電壓值的N分之一，其中N可為不小於1的正實數。在本實施例中，N等於2，亦即當電壓值v_out增加至電源電壓V_DD的電壓值的一半時，即到達揚聲器的工作電壓而停止進行預充電，以縮短揚聲器140的啟動時間。然而，所述之N值可由設計者依據設計需求自行更動，本發明不以此為限。It should be noted that the preset voltage value v_p is equal to one-Nth of the voltage value of the power supply voltage V_DD received by the audio amplifying device 100, where N may be a positive real number not less than one. In the present embodiment, N is equal to 2, that is, when the voltage value v_out is increased to half of the voltage value of the power supply voltage V_DD, that is, the operating voltage of the speaker is reached and the pre-charging is stopped to shorten the startup time of the speaker 140. However, the value of N can be changed by the designer according to the design requirements, and the invention is not limited thereto.

另一方面，當電壓值v_out等於預設電壓值v_p時，第二放大模組130依據致能的第二控制信號s_c2接收音訊信號s_a，以產生第二放大信號s_c2。此外，由於第一控制信號s_c1對應被禁能，因此第一放大模組120將停止產生第一放大信號s_c2。On the other hand, when the voltage value v_out is equal to the preset voltage value v_p, the second amplifying module 130 receives the audio signal s_a according to the enabled second control signal s_c2 to generate the second amplified signal s_c2. In addition, since the first control signal s_c1 is disabled, the first amplification module 120 will stop generating the first amplified signal s_c2.

換句話說，當音訊放大裝置100開啟時，預充電單元110對輸出端OT進行預充電，並經過預充電期間t_soft後將輸出端OT偏壓至預定電壓值v_p。此時，音訊放大裝置100自驅動能力較低的第一放大模組120切換至驅動能力較高的第二放大模組130以放大音訊信號s_a。In other words, when the audio amplifying device 100 is turned on, the pre-charging unit 110 pre-charges the output terminal OT, and after the pre-charging period t_soft, biases the output terminal OT to a predetermined voltage value v_p. At this time, the audio amplifying device 100 is switched from the first amplifying module 120 having a lower driving capability to the second amplifying module 130 having a higher driving capability to amplify the audio signal s_a.

詳細而言，第一放大模組120與第二放大模組130依據輸出端OT的預充電狀態而相互切換。當預充電單元110進行預充電時，具有相對低驅動能力的第一放大模組120在依據音訊信號s_a輸出第一放大信號s_amp1的同時，亦建立了其輸入端與輸出端的電壓準位。其中，在預充電期間t_soft內，由於輸出端OT上的電壓值v_out仍低於預設電壓值v_p，且第一放大信號s_amp1為相對低驅動能力的放大信號，因此揚聲器140並不會發出不需要的聲音。In detail, the first amplifying module 120 and the second amplifying module 130 are mutually switched according to the pre-charging state of the output terminal OT. When the pre-charging unit 110 performs pre-charging, the first amplifying module 120 having a relatively low driving capability simultaneously establishes the voltage level of the input end and the output end thereof while outputting the first amplifying signal s_amp1 according to the audio signal s_a. In the pre-charge period t_soft, since the voltage value v_out on the output terminal OT is still lower than the preset voltage value v_p, and the first amplified signal s_amp1 is an amplified signal with a relatively low driving capability, the speaker 140 does not emit no The sound you need.

當預充電停止時，音訊放大裝置100自第一放大模組120切換至利用第二放大模組130驅動揚聲器140。此時，由於在預充電期間t_soft，第一放大模組120已經提前將其輸入端與輸出端的電壓準位建立，因此，當音訊放大裝置100切換至第二放大模組130時，具有較高驅動能力的第二放大模組130可直接依據第一放大模組120所建立之電壓準位放大音訊信號s_a。此外，由於揚聲器140已被偏壓至正常操作的電壓下，因此揚聲器140可依據第二放大信號s_amp2正常的輸出聲音。When the pre-charging is stopped, the audio amplifying device 100 is switched from the first amplifying module 120 to the second amplifying module 130 to drive the speaker 140. At this time, since the first amplifying module 120 has established the voltage level of its input end and the output end in advance during the pre-charging period t_soft, when the audio amplifying device 100 switches to the second amplifying module 130, it has a higher The second amplifying module 130 of the driving capability can directly amplify the audio signal s_a according to the voltage level established by the first amplifying module 120. Furthermore, since the speaker 140 has been biased to a voltage that is normally operated, the speaker 140 can output a sound normally according to the second amplified signal s_amp2.

相較於一般具有預充電功能之功率放大器，其可能在預充電停止至正常操作的期間內，由於功率放大器的突然導通而產生之突波電流，可能使揚聲器產生爆音雜訊。本實施例之音訊放大裝置100在預充電期間內即建立起放大模組的電壓準位，以使預充電停止至正常操作的期間內，第一放大模組120能夠近乎無縫地切換至第二放大模組130，以降低爆音雜訊發生的機率。Compared to a power amplifier that generally has a precharge function, it may cause a surge current due to the sudden turn-on of the power amplifier during the period from the precharge stop to the normal operation, which may cause the speaker to generate pop noise. The audio amplifying device 100 of the embodiment establishes the voltage level of the amplifying module during the pre-charging period, so that the first amplifying module 120 can switch to the first seamlessly during the period from the pre-charging to the normal operation. The second amplification module 130 is configured to reduce the probability of occurrence of pop noise.

為了更清楚的描述本發明實施例，圖3繪示本發明一實施例之音訊放大裝置300的電路架構圖。請參照圖3，音訊放大裝置300同樣包括預充電單元310、第一放大模組320以及第二放大模組330。此外，音訊放大裝置300更包括第一回授電阻R_f1與第二回授電阻R_f2，耦接於音訊放大裝置300的輸入端與輸出端OT之間，用以提供第一放大模組320與第二放大模組330負回授的信號路徑。其中，第一回授電阻R_f1與第二回授電阻R_f2決定了音訊放大裝置300整體的信號放大增益為第二回授電阻R_f2的電阻值除以第一回授電阻R_f1的電阻值。In order to more clearly describe the embodiments of the present invention, FIG. 3 is a circuit diagram of an audio amplification device 300 according to an embodiment of the present invention. Referring to FIG. 3 , the audio amplification device 300 also includes a pre-charging unit 310 , a first amplifying module 320 , and a second amplifying module 330 . In addition, the audio amplifying device 300 further includes a first feedback resistor R_f1 and a second feedback resistor R_f2 coupled between the input end and the output end OT of the audio amplifying device 300 for providing the first amplifying module 320 and the first The second amplification module 330 has a negative feedback signal path. The first feedback resistor R_f1 and the second feedback resistor R_f2 determine that the signal amplification gain of the entire audio amplification device 300 is the resistance value of the second feedback resistor R_f2 divided by the resistance value of the first feedback resistor R_f1.

在本實施例中，預充電單元310包括電流源312、第一預充電開關SW_p1、第二預充電開關SW_p2、延遲電容C_d、延遲電阻R_d、比較器314以及閂鎖器316。In the present embodiment, the pre-charging unit 310 includes a current source 312, a first pre-charge switch SW_p1, a second pre-charge switch SW_p2, a delay capacitor C_d, a delay resistor R_d, a comparator 314, and a latch 316.

在預充電單元310中，電流源312、第一預充電開關SW_p1、第二預充電開關SW_p2、延遲電容C_d以及延遲電阻R_d在揚聲器140的電源開啟時，提供驅動電流I_d至揚聲器140，使得輸出端OT上的電壓值v_out逐漸增加至預設電壓值v_p，以使揚聲器140正常的操作。In the pre-charging unit 310, the current source 312, the first pre-charge switch SW_p1, the second pre-charge switch SW_p2, the delay capacitor C_d, and the delay resistor R_d provide the driving current I_d to the speaker 140 when the power of the speaker 140 is turned on, so that the output The voltage value v_out on the terminal OT is gradually increased to the preset voltage value v_p to allow the speaker 140 to operate normally.

第一預充電開關SW_p1的第一端耦接電流源312，並依據第一控制信號s_c1決定是否導通。延遲電容C_d的第一端耦接第一預充電開關SW_p1的第二端，且延遲電容C_d的第二端耦接接地電壓GND。延遲電阻R_d的第一端耦接第一預充電開關SW_p1的第二端與延遲電容C_d的第一端。第二預充電開關SW_p2的第一端耦接延遲電阻R_d的第二端，其第二端耦接輸出端OT。此外，第二預充電開關SW_p2亦依據第一控制信號s_c1決定是否導通。The first end of the first pre-charge switch SW_p1 is coupled to the current source 312, and determines whether to be turned on according to the first control signal s_c1. The first end of the delay capacitor C_d is coupled to the second end of the first pre-charge switch SW_p1, and the second end of the delay capacitor C_d is coupled to the ground voltage GND. The first end of the delay resistor R_d is coupled to the second end of the first pre-charge switch SW_p1 and the first end of the delay capacitor C_d. The first end of the second pre-charge switch SW_p2 is coupled to the second end of the delay resistor R_d, and the second end of the second pre-charge switch SW_p2 is coupled to the output end OT. In addition, the second pre-charge switch SW_p2 also determines whether to conduct according to the first control signal s_c1.

具體而言，請同時參照圖2與圖3，當揚聲器140的電源開啟時，第一控制信號s_c1被致能而使第一預充電開關SW_p1與第二預充電開關SW_p2導通。因此，電流源312依據電源電壓V_DD所提供的驅動電流I_d得以藉由延遲電容C_d與延遲電阻R_d所組成的RC電路，而使輸出端OT上的電壓值v_out在預充電期間內逐漸地增加。其中，預充電期間的長短係由延遲電容C_d與延遲電阻R_d的RC時間常數(RC time constant)所決定。此外，當延遲電阻R_d的電阻值遠大於揚聲器140的負載的電阻值時，揚聲器140的負載的跨壓就越低，而越能夠減少爆音雜訊。因此在電路設計中，通常選擇具有較大電阻值的延遲電阻R_d以減少揚聲器140的爆音雜訊。Specifically, referring to FIG. 2 and FIG. 3 simultaneously, when the power of the speaker 140 is turned on, the first control signal s_c1 is enabled to turn on the first pre-charge switch SW_p1 and the second pre-charge switch SW_p2. Therefore, the current source 312 can cause the voltage value v_out at the output terminal OT to gradually increase during the precharge period by the RC circuit composed of the delay capacitor C_d and the delay resistor R_d according to the driving current I_d supplied from the power source voltage V_DD. The length of the precharge period is determined by the RC time constant of the delay capacitor C_d and the delay resistor R_d. Further, when the resistance value of the delay resistor R_d is much larger than the resistance value of the load of the speaker 140, the crossover voltage of the load of the speaker 140 is lower, and the popping noise can be reduced. Therefore, in the circuit design, the delay resistor R_d having a large resistance value is usually selected to reduce the popping noise of the speaker 140.

另一方面，在預充電單元310中，比較器314以及閂鎖器316依據電壓值v_out判斷是否致能第二控制信號s_c2，以決定是否停止對揚聲器140進行預充電。此外，當第二控制信號s_c2被閂鎖器316致能時，其將使音訊放大裝置300自第一放大模組320切換至第二放大模組330，並據以放大音訊信號s_a。On the other hand, in the pre-charging unit 310, the comparator 314 and the latch 316 determine whether or not the second control signal s_c2 is enabled in accordance with the voltage value v_out to decide whether to stop precharging the speaker 140. In addition, when the second control signal s_c2 is enabled by the latch 316, it will cause the audio amplifying device 300 to switch from the first amplifying module 320 to the second amplifying module 330, and thereby amplify the audio signal s_a.

比較器314的第一輸入端耦接預設電壓V_P，其第二輸入端耦接第二預充電開關SW_p2的第二端以及輸出端OT，且其輸出端依據電壓值v_out與預設電壓值v_p的比較結果產生比較信號s_comp。閂鎖器316耦接比較器314的輸出端，以依據閂鎖比較信號s_comp來產生第二控制信號s_c2。The first input end of the comparator 314 is coupled to the preset voltage V_P, the second input end is coupled to the second end of the second pre-charge switch SW_p2 and the output end OT, and the output end thereof is based on the voltage value v_out and the preset voltage value. The comparison result of v_p produces a comparison signal s_comp. The latch 316 is coupled to the output of the comparator 314 to generate a second control signal s_c2 in accordance with the latch comparison signal s_comp.

具體而言，在預充電期間內，輸出端OT上的電壓值v_out將持續的增加而趨近於預設電壓值v_p，直到當比較器314判斷電壓值v_out等於預設電壓V_P所提供的預設電壓值v_p時，比較器314將於其輸出端產生致能的比較信號s_comp，而使閂鎖器316致能第二控制信號s_c2。此時，由於第二控制信號s_c2被致能，將使得第一控制信號s_c1同時對應的被禁能。換言之，第一控制信號s_c1與第二控制信號s_c2在本實施例中互為反相。因此，第一預充電開關SW_p1與第二預充電開關SW_p2依據禁能的第一控制信號s_c1而截止，使預充電單元310停止對揚聲器140進行預充電的動作。Specifically, during the precharge period, the voltage value v_out on the output terminal OT will continuously increase to approach the preset voltage value v_p until the comparator 314 determines that the voltage value v_out is equal to the preset provided by the preset voltage V_P. When the voltage value v_p is set, the comparator 314 will generate an enable comparison signal s_comp at its output, and cause the latch 316 to enable the second control signal s_c2. At this time, since the second control signal s_c2 is enabled, the first control signal s_c1 will be disabled at the same time. In other words, the first control signal s_c1 and the second control signal s_c2 are mutually inverted in this embodiment. Therefore, the first pre-charge switch SW_p1 and the second pre-charge switch SW_p2 are turned off according to the disabled first control signal s_c1, and the pre-charging unit 310 stops the action of pre-charging the speaker 140.

換句話說，當預充電單元310判斷電壓值v_out不等於預設電壓值v_p時，第一預充電開關SW_p1與第二預充電開關SW_p2依據第一控制信號s_c1而導通，而對揚聲器140進行預充電。相反地，當預充電單元310判斷電壓值v_out等於預設電壓值v_p時，第一預充電開關SW_p1與第二預充電開關SW_p2依據第一控制信號s_c1截止，以停止對揚聲器140進行預充電。In other words, when the pre-charging unit 310 determines that the voltage value v_out is not equal to the preset voltage value v_p, the first pre-charge switch SW_p1 and the second pre-charge switch SW_p2 are turned on according to the first control signal s_c1, and the speaker 140 is pre- Charging. Conversely, when the pre-charging unit 310 determines that the voltage value v_out is equal to the preset voltage value v_p, the first pre-charge switch SW_p1 and the second pre-charge switch SW_p2 are turned off according to the first control signal s_c1 to stop pre-charging the speaker 140.

在本實施例中，第一放大模組320包括第一放大器OP1、第一電容C_1、第一電阻R_1、第一開關SW_1以及第二開關SW_2。第一放大器OP1的輸入端接收音訊信號s_a，且其輸出端輸出第一放大信號s_amp1。第一電容C_1的第一端耦接第一放大器OP1的輸入端，且其第二端耦接第一放大器OP1的輸出端，其中第一電容C_1係為相位補償電容，用以確保第一放大器OP1操作的相位裕度(phase margin)。第一開關SW_1的第一端接收音訊信號s_a，且其第二端耦接第一放大器OP1的輸入端與第一電容C_1的第一端，其中第一開關SW_1依據第一控制信號s_c1決定是否導通。第一電阻R_1的第一端耦接第一放大器OP1的輸出端。第二開關SW_2的第一端耦接第一電阻R_1的第二端，且其第二端耦接第一放大器OP1的輸出端。In this embodiment, the first amplification module 320 includes a first amplifier OP1, a first capacitor C_1, a first resistor R_1, a first switch SW_1, and a second switch SW_2. The input end of the first amplifier OP1 receives the audio signal s_a, and the output thereof outputs the first amplified signal s_amp1. The first end of the first capacitor C_1 is coupled to the input end of the first amplifier OP1, and the second end is coupled to the output end of the first amplifier OP1, wherein the first capacitor C_1 is a phase compensation capacitor to ensure the first amplifier The phase margin of the OP1 operation. The first end of the first switch SW_1 receives the audio signal s_a, and the second end is coupled to the input end of the first amplifier OP1 and the first end of the first capacitor C_1, wherein the first switch SW_1 determines whether the first control signal s_c1 is based on the first control signal s_c1 Turn on. The first end of the first resistor R_1 is coupled to the output end of the first amplifier OP1. The first end of the second switch SW_2 is coupled to the second end of the first resistor R_1, and the second end thereof is coupled to the output end of the first amplifier OP1.

相似地，第二放大模組320包括第二放大器OP2、第二電容C_2以及第三開關SW_3。第二放大器OP2的輸入端接收音訊信號s_a，且其輸出端輸出第二放大信號s_amp2。第二電容C_2的第一端耦接第二放大器OP2的輸入端，且其第二端耦接第二放大器OP2的輸出端，其中第二電容C_2係為相位補償電容，用以確保第二放大器OP2操作的相位裕度。第三開關SW_3的第一端接收音訊信號s_a，且其第二端耦接第二放大器OP2的輸入端與第二電容的第一端，其中第三開關SW_3依據第二控制信號s_c2決定是否導通。Similarly, the second amplification module 320 includes a second amplifier OP2, a second capacitor C_2, and a third switch SW_3. The input of the second amplifier OP2 receives the audio signal s_a, and the output thereof outputs the second amplified signal s_amp2. The first end of the second capacitor C_2 is coupled to the input end of the second amplifier OP2, and the second end thereof is coupled to the output end of the second amplifier OP2, wherein the second capacitor C_2 is a phase compensation capacitor to ensure the second amplifier Phase margin for OP2 operation. The first end of the third switch SW_3 receives the audio signal s_a, and the second end thereof is coupled to the input end of the second amplifier OP2 and the first end of the second capacitor, wherein the third switch SW_3 determines whether to conduct according to the second control signal s_c2 .

詳細而言，當揚聲器140的電源開啟時，第一控制信號s_c1被致能，且第二控制信號s_c2對應被禁能，使得第一放大模組320的第一開關SW_1與第二開關SW_2被導通，而第二放大模組330的第三開關SW_3被截止。因此，第一放大器OP1接收並放大音訊信號s_a以輸出第一放大信號s_amp1來驅動揚聲器140。但是由於第一放大器OP1的驅動能力較弱，且輸出端OT尚未偏壓至預設電壓值v_p，因此在預充電的階段，第一放大信號s_amp1尚不足以推動揚聲器140的負載。In detail, when the power of the speaker 140 is turned on, the first control signal s_c1 is enabled, and the second control signal s_c2 is disabled, so that the first switch SW_1 and the second switch SW_2 of the first amplification module 320 are Turning on, and the third switch SW_3 of the second amplification module 330 is turned off. Therefore, the first amplifier OP1 receives and amplifies the audio signal s_a to output the first amplified signal s_amp1 to drive the speaker 140. However, since the driving capability of the first amplifier OP1 is weak and the output terminal OT has not been biased to the preset voltage value v_p, the first amplified signal s_amp1 is not sufficient to push the load of the speaker 140 during the pre-charging phase.

值得注意的是，由於低驅動能力的第一放大器OP1可能會造成所輸出的第一放大信號s_amp1具有較為嚴重的雜訊干擾，因此在設計時需要選擇電阻值較大的第一電阻R_1，以使第一放大信號s_amp1的雜訊最小化。It is worth noting that, because the first amplifier OP1 with low driving capability may cause the first amplified signal s_amp1 to be output to have relatively serious noise interference, it is necessary to select the first resistor R_1 with a large resistance value during design. The noise of the first amplified signal s_amp1 is minimized.

在預充電期間中，輸出端OT上的電壓值v_out持續增加，直到電壓值v_out等於預設電壓值v_p時，第二控制信號s_c2被預充電單元310致能，而第一控制信號s_c1則對應被禁能，使得第一放大模組320的第一開關SW_1與第二開關SW_2依據禁能的第一控制信號s_C1被截止，而第二放大模組330的第三開關SW_3依據致能的第二控制信號s_c2被導通。換句話說，此時音訊放大裝置300自第一放大模組320切換至利用第二放大模組330放大音訊信號s_a。其中，第二放大器OP2接收並放大音訊信號s_a以輸出第二放大信號s_amp2來驅動揚聲器140。由於第二放大器OP2具有很高的驅動能力，且此時輸出端OT亦被偏壓至預設電壓值v_p，因此揚聲器140可正常的依據第二放大信號s_amp2輸出聲音。During the pre-charging period, the voltage value v_out on the output terminal OT continues to increase until the voltage value v_out is equal to the preset voltage value v_p, the second control signal s_c2 is enabled by the pre-charging unit 310, and the first control signal s_c1 corresponds to The first switch SW_1 and the second switch SW_2 of the first amplification module 320 are disabled according to the disabled first control signal s_C1, and the third switch SW_3 of the second amplification module 330 is enabled according to the enablement. The second control signal s_c2 is turned on. In other words, at this time, the audio amplifying device 300 is switched from the first amplifying module 320 to the second amplifying module 330 to amplify the audio signal s_a. The second amplifier OP2 receives and amplifies the audio signal s_a to output the second amplified signal s_amp2 to drive the speaker 140. Since the second amplifier OP2 has a high driving capability, and at this time, the output terminal OT is also biased to the preset voltage value v_p, the speaker 140 can normally output the sound according to the second amplified signal s_amp2.

值得注意的是，由於第二放大器OP2的輸入端與輸出端的電壓準位在預充電期間即藉由第一放大模組310的驅動先行建立，因此當預充電停止時，第二放大器OP2可依據已經建立的電壓準位放大音訊信號s_a，以使預充電結束切換至正常操作時所產生的爆音雜訊得以降到最低。It should be noted that, since the voltage level of the input end and the output end of the second amplifier OP2 is established by the driving of the first amplifying module 310 during the pre-charging period, when the pre-charging is stopped, the second amplifier OP2 can be based on The established voltage level amplifies the audio signal s_a to minimize the pop noise generated when the precharge is switched to normal operation.

圖4繪示本發明一實施例之音訊放大裝置400的電路架構圖。在本實施例中，音訊放大裝置400與圖3實施例之音訊放大裝置300之差異在於音訊放大裝置400加入了前置放大器以預先放大音訊信號s_a。FIG. 4 is a circuit diagram of an audio amplifying apparatus 400 according to an embodiment of the present invention. In the present embodiment, the difference between the audio amplifying device 400 and the audio amplifying device 300 of the embodiment of FIG. 3 is that the audio amplifying device 400 incorporates a preamplifier to preamplify the audio signal s_a.

請參照圖4，音訊放大裝置400更包括前置放大器402。前置放大器402的第一輸入端分別經由第一回授電阻R_f1以及第二回授電阻R_f2耦接音訊放大裝置400的輸入端以及輸出端OT，其第二輸入端耦接預設電壓V_P，且其輸出端耦接第一放大器模組320與第二放大模組330。其中，前置放大器402在音訊信號s_a輸入第一放大模組320或第二放大模組330之前，進一步地預先放大音訊信號sa來抑制後級的第一放大模組320或第二放大模組330的雜訊影響，以減少爆音雜訊的產生。Referring to FIG. 4, the audio amplification device 400 further includes a preamplifier 402. The first input end of the preamplifier 402 is coupled to the input end of the audio amplifying device 400 and the output end OT via a first feedback resistor R_f1 and a second feedback resistor R_f2, and the second input end is coupled to the preset voltage V_P. The output end is coupled to the first amplifier module 320 and the second amplification module 330. The preamplifier 402 further pre-amplifies the audio signal sa to suppress the first amplification module 320 or the second amplification module of the subsequent stage before the audio signal s_a is input to the first amplification module 320 or the second amplification module 330. The noise of 330 is used to reduce the generation of pop noise.

除此之外，音訊放大裝置400與音訊放大裝置300的電路結構相同，因此音訊放大裝置400中的元件特性說明請參照圖3實施例，於此處不再贅述。此外，相對於揚聲器140電源開啟的狀態，當電源關閉時亦可利用相對於上述實施例之充電過程的放電過程，進而降低關閉電源時的爆音雜訊。此為本領域通常知識者參閱上述實施例後，可由所述之實施例中輕易推論出，故不再贅述。In addition, the audio amplifying device 400 and the audio amplifying device 300 have the same circuit configuration. Therefore, please refer to FIG. 3 for the description of the component characteristics in the audio amplifying device 400, and details are not described herein again. In addition, with respect to the state in which the power of the speaker 140 is turned on, the discharge process with respect to the charging process of the above embodiment can also be utilized when the power is turned off, thereby reducing the popping noise when the power is turned off. This is a general knowledge of the above-mentioned embodiments, and can be easily inferred from the above-described embodiments, and therefore will not be described again.

綜上所述，本發明實施例之音訊放大裝置利用預充電單元對揚聲器進行預充電，以逐漸地提升音訊放大裝置的輸出端上的電壓值，並且依據預充電的狀態切換具有不同驅動能力的放大模組，使得揚聲器自預充電狀態切換至正常操作時所可能產生的突波電流得以被有效地消除。此外，由於在預充電期間音訊放大裝置已預先建立其放大模組內部的電壓準位，使得揚聲器的電源開啟後得以快速進入正常操作狀態。因此，本發明實施例有效地降低了揚聲器電源開啟或關閉時的爆音雜訊，同時亦縮短了揚聲器的開機速度，進而提升了使用者收聽的品質與舒適度。In summary, the audio amplifying device of the embodiment of the present invention precharges the speaker by using a pre-charging unit to gradually increase the voltage value at the output end of the audio amplifying device, and switches the driving capability with different driving capabilities according to the pre-charging state. The amplification module allows the spur current that may be generated when the speaker is switched from the pre-charge state to the normal operation to be effectively eliminated. In addition, since the audio amplifying device has previously established the voltage level inside the amplifying module during pre-charging, the power of the speaker is turned on and quickly enters the normal operating state. Therefore, the embodiment of the invention effectively reduces the popping noise when the speaker power is turned on or off, and also shortens the booting speed of the speaker, thereby improving the quality and comfort of the user.

雖然本發明已以實施例揭露如上，然其並非用以限定本發明，任何所屬技術領域中具有通常知識者，在不脫離本發明之精神和範圍內，當可作些許之更動與潤飾，故本發明之保護範圍當視後附之申請專利範圍所界定者為準。Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100．．．音訊放大裝置100. . . Audio amplification device

110．．．預充電單元110. . . Precharge unit

120．．．第一放大模組120. . . First amplification module

130．．．第二放大模組130. . . Second amplification module

140．．．揚聲器140. . . speaker

300．．．音訊放大裝置300. . . Audio amplification device

310．．．預充電單元310. . . Precharge unit

312．．．電流源312. . . Battery

314．．．比較器314. . . Comparators

316．．．閂鎖器316. . . Latch

320．．．第一放大模組320. . . First amplification module

330．．．第二放大模組330. . . Second amplification module

R_f1．．．第一回授電阻R_f1. . . First feedback resistor

R_f2．．．第二回授電阻R_f2. . . Second feedback resistor

R_1．．．第一電阻R_1. . . First resistance

R_d．．．延遲電阻R_d. . . Delay resistor

C_1．．．第一電容C_1. . . First capacitor

C_2．．．第二電容C_2. . . Second capacitor

C_d．．．延遲電容C_d. . . Delay capacitor

GND．．．接地電壓GND. . . Ground voltage

I_d．．．驅動電流I_d. . . Drive current

OT．．．輸出端OT. . . Output

OP1．．．第一放大器OP1. . . First amplifier

OP2．．．第二放大器OP2. . . Second amplifier

SW_1．．．第一開關SW_1. . . First switch

SW_2．．．第二開關SW_2. . . Second switch

SW_3．．．第三開關SW_3. . . Third switch

SW_p1．．．第一預充電開關SW_p1. . . First pre-charge switch

SW_p2．．．第二預充電開關SW_p2. . . Second pre-charge switch

s_c1．．．第一控制信號S_c1. . . First control signal

s_c2．．．第二控制信號S_c2. . . Second control signal

s_comp．．．比較信號S_comp. . . Comparison signal

s_amp1．．．第一放大信號S_amp1. . . First amplified signal

s_amp2．．．第二放大信號S_amp2. . . Second amplified signal

s_a．．．音訊信號S_a. . . Audio signal

t．．．充電時間t. . . Charging time

t_soft．．．預充電期間T_soft. . . Precharge period

V_DD．．．電源電壓V_DD. . . voltage

V_PP．．．預設電壓V_PP. . . Preset voltage

v_out．．．電壓值V_out. . . Voltage value

v_p．．．預設電壓值V_p. . . Preset voltage value

圖1繪示本發明一實施例之音訊放大裝置100的示意圖。FIG. 1 is a schematic diagram of an audio amplifying apparatus 100 according to an embodiment of the present invention.

圖2繪示依照圖1實施例之輸出端OT的暫態響應的示意圖。2 is a schematic diagram showing the transient response of the output terminal OT according to the embodiment of FIG. 1.

圖3繪示本發明一實施例之音訊放大裝置300的電路架構圖。FIG. 3 is a circuit diagram of an audio amplification device 300 according to an embodiment of the present invention.

圖4繪示本發明一實施例之音訊放大裝置400的電路架構圖。FIG. 4 is a circuit diagram of an audio amplifying apparatus 400 according to an embodiment of the present invention.

100．．．音訊放大裝置100. . . Audio amplification device

110．．．預充電單元110. . . Precharge unit

120．．．第一放大模組120. . . First amplification module

130．．．第二放大模組130. . . Second amplification module

140．．．揚聲器140. . . speaker

I_d．．．驅動電流I_d. . . Drive current

OT．．．輸出端OT. . . Output

s_amp1．．．第一放大信號S_amp1. . . First amplified signal

s_amp2．．．第二放大信號S_amp2. . . Second amplified signal

s_C1．．．第一控制信號s_C1. . . First control signal

s_C2．．．第二控制信號s_C2. . . Second control signal

s_a．．．音訊信號S_a. . . Audio signal

V_DD．．．電源電壓V_DD. . . voltage

Claims (16)

一種音訊放大裝置，適於驅動一揚聲器，該音訊放大裝置包括：一預充電單元，透過一輸出端耦接該揚聲器，依據一第一控制信號提供一驅動電流對該揚聲器進行預充電，以逐漸地增加該輸出端上的電壓值；一第一放大模組，耦接至該輸出端，用以依據該第一控制信號來接收一音訊信號，並放大該音訊信號以輸出一第一放大信號來驅動該揚聲器；以及一第二放大模組，耦接至該輸出端，用以依據一第二控制信號來接收該音訊信號，並放大該音訊信號以輸出一第二放大信號來驅動該揚聲器，其中該預充電單元依據比對該輸出端上的電壓值以及一預設電壓值來產生該第二控制信號，其中當該輸出端上的該電壓值小於該預設電壓值時，僅有該第一放大模組回應於該第一控制信號而放大該音訊信號以輸出該第一放大信號來驅動該揚聲器，其中當該輸出端上的該電壓值達到該預設電壓值時，僅有該第二放大模組回應於該第二控制信號而放大該音訊信號以輸出該第二放大信號來驅動該揚聲器。 An audio amplifying device is adapted to drive a speaker. The audio amplifying device comprises: a pre-charging unit coupled to the speaker through an output terminal, and a driving current is provided according to a first control signal to pre-charge the speaker to gradually Adding a voltage value at the output end; a first amplifying module coupled to the output end for receiving an audio signal according to the first control signal, and amplifying the audio signal to output a first amplified signal And driving the speaker; and a second amplifying module coupled to the output end for receiving the audio signal according to a second control signal, and amplifying the audio signal to output a second amplified signal to drive the speaker The pre-charging unit generates the second control signal according to a voltage value on the output terminal and a preset voltage value, wherein when the voltage value on the output terminal is less than the preset voltage value, only The first amplification module amplifies the audio signal in response to the first control signal to output the first amplified signal to drive the speaker, wherein the output terminal When this voltage reaches the predetermined voltage value, only the second amplifier module in response to the second control signal and amplifies the audio signal to output the amplified signal to drive the second loudspeaker. 如申請專利範圍第1項所述之音訊放大裝置，其中該第一放大模組的驅動能力低於該第二放大模組的驅動能力。 The audio amplifying device of claim 1, wherein the driving capability of the first amplifying module is lower than the driving capability of the second amplifying module. 如申請專利範圍第1項所述之音訊放大裝置，其中該預設電壓值等於該音訊放大裝置所接收的電源電壓的電壓值的N分之一，N為不小於1的正實數。 The audio amplifying device of claim 1, wherein the preset voltage value is equal to one-Nth of a voltage value of the power supply voltage received by the audio amplifying device, and N is a positive real number not less than one. 如申請專利範圍第1項所述之音訊放大裝置，其中當該預充電單元判斷該輸出端上的電壓值等於該預設電壓值時，該預充電單元使該第二控制信號致能，並藉以使該第二放大模組接收該音訊信號，以產生該第二放大信號。 The audio amplifying device of claim 1, wherein the pre-charging unit enables the second control signal when the pre-charging unit determines that the voltage value at the output terminal is equal to the preset voltage value, and The second amplification module receives the audio signal to generate the second amplified signal. 如申請專利範圍第4項所述之音訊放大裝置，其中當該第二控制信號被致能時，該第一控制信號對應被禁能，使該預充電單元停止對該揚聲器所進行的預充電動作，並使該第一放大模組停止接收該音訊信號。 The audio amplifying device of claim 4, wherein when the second control signal is enabled, the first control signal is disabled correspondingly, and the pre-charging unit stops pre-charging the speaker. Acting and causing the first amplification module to stop receiving the audio signal. 如申請專利範圍第1項所述之音訊放大裝置，其中該第一放大模組包括：一第一放大器，具有輸入端與輸出端，該第一放大器的輸入端接收該音訊信號，且該第一放大器的輸出端輸出該第一放大信號；以及一第一電容，具有第一端與第二端，該第一電容的第一端耦接該第一放大器的輸入端，且該第一電容的第二端耦接該第一放大器的輸出端。 The audio amplification device of claim 1, wherein the first amplification module comprises: a first amplifier having an input end and an output end, the input end of the first amplifier receiving the audio signal, and the An output of the amplifier outputs the first amplified signal; and a first capacitor has a first end and a second end, the first end of the first capacitor is coupled to the input end of the first amplifier, and the first capacitor The second end is coupled to the output of the first amplifier. 如申請專利範圍第6項所述之音訊放大裝置，其中該第一放大模組更包括：一第一電阻，具有第一端與第二端，該第一電阻的第一端耦接該第一放大器的輸出端；一第一開關，具有第一端與第二端，依據該第一控制信號決定是否導通，該第一開關的第一端接收該音訊信號，且該第一開關的第二端耦接該第一放大器的輸入端與該第一電容的第一端；以及一第二開關，具有第一端與第二端，依據該第一控制信號 決定是否導通，該第二開關的第一端耦接該第一電阻的第二端，且該第二開關的第二端耦接該第一放大器的輸出端，其中當該輸出端上的電壓值不等於該預設電壓值時，該第一開關與該第二開關依據該第一控制信號而導通，以及當該輸出端上的電壓值等於該預設電壓值時，該第一開關與該第二開關依據該第一控制信號而截止。 The audio amplifying device of claim 6, wherein the first amplifying module further comprises: a first resistor having a first end and a second end, wherein the first end of the first resistor is coupled to the first end An output of an amplifier; a first switch having a first end and a second end, determining whether to conduct according to the first control signal, the first end of the first switch receiving the audio signal, and the first switch The second end is coupled to the input end of the first amplifier and the first end of the first capacitor; and the second switch has a first end and a second end, according to the first control signal Deciding whether to conduct, the first end of the second switch is coupled to the second end of the first resistor, and the second end of the second switch is coupled to the output end of the first amplifier, wherein the voltage on the output end When the value is not equal to the preset voltage value, the first switch and the second switch are turned on according to the first control signal, and when the voltage value on the output terminal is equal to the preset voltage value, the first switch is The second switch is turned off according to the first control signal. 如申請專利範圍第6項所述之音訊放大裝置，其中該第二放大模組包括：一第二放大器，具有輸入端與輸出端，該第二放大器的輸入端接收該音訊信號，且該第二放大器的輸出端輸出該第二放大信號；以及一第二電容，具有第一端與第二端，該第二電容的第一端耦接該第二放大器的輸入端，且該第二電容的第二端耦接該第二放大器的輸出端。 The audio amplifying device of claim 6, wherein the second amplifying module comprises: a second amplifier having an input end and an output end, the input end of the second amplifier receiving the audio signal, and the An output of the second amplifier outputs the second amplified signal; and a second capacitor has a first end and a second end, the first end of the second capacitor is coupled to the input end of the second amplifier, and the second capacitor The second end is coupled to the output of the second amplifier. 如申請專利範圍第8項所述之音訊放大裝置，其中該第二放大模組更包括：一第三開關，具有第一端與第二端，依據該第二控制信號決定是否導通，該第三開關的第一端接收該音訊信號，且該第三開關的第二端耦接該第二放大器的輸入端與該第二電容的第一端，其中當該輸出端上的電壓值不等於該預設電壓值時，該第三開關依據該第二控制信號而截止，以及當該輸出端上的電壓值等於該預設電壓值時，該第三開關依據該第二控制信號而導通。 The audio amplifying device of claim 8, wherein the second amplifying module further comprises: a third switch having a first end and a second end, determining whether to conduct according to the second control signal, the first The first end of the third switch receives the audio signal, and the second end of the third switch is coupled to the input end of the second amplifier and the first end of the second capacitor, wherein when the voltage value on the output is not equal When the voltage value is preset, the third switch is turned off according to the second control signal, and when the voltage value on the output terminal is equal to the preset voltage value, the third switch is turned on according to the second control signal. 如申請專利範圍第8項所述之音訊放大裝置，更包括： 一第一回授電阻，具有第一端與第二端，該第一回授電阻的第一端接收該音訊信號，且該第一回授電阻的第二端耦接該第一放大器與該第二放大器的輸入端；以及一第二回授電阻，具有第一端與第二端，該第一回授電阻的第一端耦接該第二電阻的第二端以及該第一放大器與該第二放大器的輸入端，且該第二回授電阻的第二端耦接該預充電單元以及該第一放大器與該第二放大器的輸出端。 The audio amplifying device of claim 8, further comprising: a first feedback resistor having a first end and a second end, the first end of the first feedback resistor receiving the audio signal, and the second end of the first feedback resistor is coupled to the first amplifier and the An input end of the second amplifier; and a second feedback resistor having a first end and a second end, the first end of the first feedback resistor being coupled to the second end of the second resistor and the first amplifier and An input end of the second amplifier, and a second end of the second feedback resistor is coupled to the pre-charging unit and the output ends of the first amplifier and the second amplifier. 如申請專利範圍第8項所述之音訊放大裝置，更包括：一前置放大器，具有第一輸入端、第二輸入端與輸出端，該前置放大器的第一輸入端耦接該輸出端，該前置放大器的第二輸入端耦接一預設電壓，且該前置放大器的輸出端耦接該第一放大模組與該第二放大模組。 The audio amplifying device of claim 8, further comprising: a preamplifier having a first input end, a second input end and an output end, wherein the first input end of the preamplifier is coupled to the output end The second input end of the preamplifier is coupled to a predetermined voltage, and the output end of the preamplifier is coupled to the first amplifying module and the second amplifying module. 如申請專利範圍第1項所述之音訊放大裝置，其中該預充電單元包括：一電流源，依據電源電壓提供該驅動電流；一第一預充電開關，具有第一端與第二端，依據該第一控制信號決定是否導通，其中該第一預充電開關的第一端耦接該電流源；一延遲電容，具有第一端與第二端，該延遲電容的第一端耦接該第一預充電開關的第二端，且該延遲電容的第二端耦接一接地電壓；以及一延遲電阻，具有第一端與第二端，該延遲電阻的第一端耦接該第一預充電開關的第二端與該延遲電容的第一端，且該延遲電阻的第二端耦接該第一放大模組與該第二放大模組， 其中當該第一預充電開關依據該第一控制信號而導通時，該驅動電流藉由該延遲電容與該延遲電阻逐漸增加該輸出端上的電壓值。 The audio amplifying device of claim 1, wherein the pre-charging unit comprises: a current source, the driving current is provided according to a power supply voltage; and a first pre-charging switch having a first end and a second end, according to The first control signal is determined to be conductive, wherein the first end of the first pre-charge switch is coupled to the current source; the delay capacitor has a first end and a second end, and the first end of the delay capacitor is coupled to the first a second end of the precharge switch, and a second end of the delay capacitor coupled to a ground voltage; and a delay resistor having a first end and a second end, the first end of the delay resistor coupled to the first pre The second end of the charging switch is coupled to the first end of the delay capacitor, and the second end of the delay resistor is coupled to the first amplifying module and the second amplifying module, When the first pre-charge switch is turned on according to the first control signal, the driving current gradually increases the voltage value at the output terminal by the delay capacitor and the delay resistor. 如申請專利範圍第12項所述之音訊放大裝置，其中該預充電單元更包括：一第二預充電開關，具有第一端與第二端，依據該第一控制信號決定是否導通，其中該第二預充電開關的第一端耦接該延遲電阻的第二端，且該第二預充電開關的第二端耦接該輸出端。 The audio amplifying device of claim 12, wherein the pre-charging unit further comprises: a second pre-charging switch having a first end and a second end, determining whether to conduct according to the first control signal, wherein the pre-charging The first end of the second pre-charge switch is coupled to the second end of the delay resistor, and the second end of the second pre-charge switch is coupled to the output end. 如申請專利範圍第13項所述之音訊放大裝置，其中當該預充電單元判斷該輸出端上的電壓值不等於該預設電壓值時，該第一預充電開關與該第二預充電開關依據該第一控制信號而導通，以及當該預充電單元判斷該輸出端上的電壓值等於該預設電壓值時，該第一預充電開關與該第二預充電開關依據該第一控制信號而截止。 The audio amplifying device of claim 13, wherein the first pre-charging switch and the second pre-charging switch are when the pre-charging unit determines that the voltage value at the output terminal is not equal to the preset voltage value. Turning on according to the first control signal, and when the pre-charging unit determines that the voltage value on the output terminal is equal to the preset voltage value, the first pre-charge switch and the second pre-charge switch are in accordance with the first control signal And the deadline. 如申請專利範圍第13項所述之音訊放大裝置，其中該預充電單元更包括：一比較器，具有第一輸入端、第二輸入端與輸出端，該比較器的第一輸入端耦接一預設電壓，該比較器的第二輸入端耦接該第二預充電開關的第二端以及該輸出端，且該比較器的輸出端輸出一比較信號，其中該比較器依據該輸出端上的電壓值以及該預設電壓提供的該預設電壓值的比對結果產生該比較信號；以及一閂鎖器，耦接該比較器的輸出端，依據閂鎖該比較信號來產生該第二控制信號。 The audio amplifying device of claim 13, wherein the precharging unit further comprises: a comparator having a first input end, a second input end and an output end, the first input end of the comparator being coupled a second input end of the comparator is coupled to the second end of the second pre-charge switch and the output end, and the output end of the comparator outputs a comparison signal, wherein the comparator is based on the output end And comparing the voltage value and the preset voltage value provided by the preset voltage to generate the comparison signal; and a latch coupled to the output of the comparator to generate the first according to the latching the comparison signal Two control signals. 如申請專利範圍第1項所述之音訊放大裝置，其中該第一控制信號與該第二控制信號互為反相。 The audio amplifying device of claim 1, wherein the first control signal and the second control signal are mutually inverted.
TW101111119A 2012-03-29 2012-03-29 Audio amplifier apparatus TWI531153B (en)

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